Luminaire for directional lighting



July 2, 1963 D. w. HARLING LUMINAIRE FOR DIRECTIONAL LIGHTING Filed Nov.4. 1960 4 MM T1 K me Vfl 4 m M p 4 w ,4 1 7% m a a k 0 m w 3 J UnitedStates Patent 3,096,030 LIE/KNARE FQR DREQTZONAL LIGHTINQ Donald W.Harling, Milwaukee, Wis assignor to Me- GraW-Edison Company, Milwaukee,Win, a corporation of Delaware Filed Nov. 4, 1969, Ser. No. 67,392 3Claims. (Cl. 240-25) This invention relates to luminaire and moreparticularly to luminaires for street or roadway lighting.

Heretofore the practice in street lighting has been to positionluminaires at regular intervals along the roadway. The lum-inairesextend over the roadway and direct light downwardly and laterally toeither side of the luminaire. Objects on the roadway are then madevisible to a driver in two very different manners; first, as the driverapproaches a particular luminaire, the luminaire is behind objects onthe roadway and such objects are seen in silhouette; and secondly, asthe driver is going away from the luminaire, objects on that side of theluminaire are illuminated by direct light and are seen by reflection.

Two major disadvantages of this type of street lighting are (l) thelaterally directed light is of equal intensity on either side of theluminaire and the luminaire has a very high glare factor to anapproaching driver, and (2) the drivers eyes must be continuallyadjusting from seeing in silhouette to seeing by reflection which placesa greater strain on his eyes and fatigue occurs more quickly.

Accordingly, it is an object of my invention to provide a streetlighting luminaire which reduces the amount of glare on the approachside thereof.

Another object of this invention is to provide a luminaire whichtransmits light in such a manner that users of a roadway seesubstantially only by reflection.

A more specific object of this invention is to provide a street lightinginstallation which produces a minimum of glare, lights objects on theroadway primarily only by reflection, and wherein there are no markedtransitions from dark to brightly lighted areas.

To accomplish these objects my invention contemplates the provisionwithin a luminaire of means so positioned with relation to theluminaires light source that it will intercept substantially all of thelight directed to one side of the luminaire and reflect the interceptedlight to the other side of the luminaire.

These and other objects and advantages of my invention will be morereadily apparent from a reading of the following description inconnection with the drawings in which:

FIG. 1 is a transverse cross sectional view of a luminaire embodying myinvention;

MG. 2 is a side elevation of the luminaire with portions of the housingand light transmitting member broken away;

FIG. 3 is a light reflection drawing for the luminaire; and,

FIG. 4 illustrates the light distribution curves for both a standardluminaire and the luminaire embodying my invention.

A luminaire 1 is supported from a vertical pole 4, at any desired heightabove a roadway or area to be lighted, by support means 5. The luminaire1 includes an upper housing 2 and a lower light transmitting member 3which is suitably connected to the housing 2. The luminaire 1 alsoincludes a reflector 6' suitably mounted within the luminaire anddividing the interior thereof into two chambers 7 and 8. The chamber 7,above the reflector 6, usually contains ballasts 10 and electricalterminals (not shown) for wiring the luminaire.

The luminaire light source is disposed immediately below the reflector 6and preferably consists of four elon- I sesame Patented .luly 2, 1963gated lamps 9, 9a, 9b and which are supported by light sockets 11located at opposed ends of the luminaires. As can be seen in the drawingthe lamps are disposed substant-ially in horizontal alignment.

The reflector '6 can be of any desired configuration and the position ofthe lamps relative thereto may be varied in accordance with the desiredlight pattern to be achieved by the luminaire 1. Also, the lighttransmitting memher 3 may be provided with exterior and/ or interiorlight retracting prisms (not shown) to further control the light emittedfrom the lamps.

The lamps emit light downwardly and laterally on either side of theluminaire 1. The reflector 6 intercepts upwardly directed light from thelamps, which light would ordinarily be Wasted, and redirects it so thatit can be utilized in lighting the roadway.

I have provided within the chamber 8 of the luminaire 1 an auxiliaryreflector 12 which is suitably supported from the reflector 6 by a pairof brackets 13. The brackets 13 are located at either end of thereflector 12 and are fixedly connected to the reflector 6 to support thereflector 12. The auxiliary reflector 12 is so poistioned within thechamber S and relative to the lamps as to intercept substan tially allof the light directed to one side of the luminaire 1 and reflect theintercepted light to the other side of the luminaire.

The reflector 12 is preferably positioned with three of lamps 9a, 9b and90 on one side thereof and the fourth lamp 9 on the other side thereof.

It is desirable to direct a limited amount of light on the approachingtraflic side of the luminaire 1 so that illumination produced by aninstallation is softened and there will be no sharp transition from darkareas to brightly ligthed areas. Hence, one lamp is positioned on theapproach side of the luminaire 1. Substantially all of the lightdirected to the left of the luminaire 1, as viewed in FIGS. 1 and 3, isintercepted by the auxiliary reflector 12 and reflected to the right ofthe luminaire 1. In this manner, the amount of light directed to theright side of the luminaire 1 i substantially increased, While at thesame time the amount of light directed to the left of the luminaire issubstantially reduced. Also, the auxiliary reflector 12 is positioned inspaced relation from the main reflector 6 so that an opening is lefttherebetween. A portion of the light emitted from the lamp 9a will bedirected to the left side of the luminaire and contribute to thesoftening effect of the installation. The light directed to the left ofthe luminaire then consists only of the light from the lamp 9 and aportion of the light from lamp 9a.

It should be noted that the auxiliary reflector 12 is provided with aconcave-convex configuration with the lamp 9 disposed on the convex sidethereof and the remainder of the lamps disposed on the concave side. Re-

7 flected light from the lamp 9 is directed, due to the convexconfiguration of the auxiliary reflector, downwardly at a low verticalangle to nadir so that this reflected light will not add to the glare onthe approaching traflic side of the luminaire.

Candle power distribution curves for a standard luminaire and aluminaire incorporating my invention are illlustrated in FIG. 4. CurvesA and A illustrate the lateral and vertical distribution, respectively,of a standard luminaire. Curves B and B illustrate the lateral andvertical distribution, respectively, of a luminaire incorporating myinvention. As illustrated, a standard luminaire emits light of equalintensity on either side of the luminaire whereas, a luminaire inaccordance with my invention directs high intensity light to only oneside of the luminaire. Substantially all of the light produced by theluminaire is directed to only one side of the luminaire, that side beingin the direction of traffic, illustrated by the arrow in FIG. 4.

Thus a driver sees objects on the roadway primarily and almostexclusively by reflection and his eyes do not have to be continuallyadjusting to see first in silhouette and then by reflection. Further, bypractically eliminating all of the light directed into the direction oftrafiic the glare factor is substantially reduced. A minor portion onlyof the generated light is directed into traffic so that the installationis softened and there are no sharp transi tional areas of light.

Although my invention has been discussed in relation to a particularpreferred embodiment, it is not intended that it be limited thereto andit is intended in the appended claims to cover all modifications andembodiments as fall within the true spirit and scope of my invention.

I claim:

1. An elongated street lighting luminaire for use above a roadway havingunidirectional travel thereon defining a forward and rearward direction,said luminaire having 7 pattern, with said rays extending vertically andalso at an 7 angle forwardly and rearwardly of said luminaire, and meansincluding a secondary reflector having a forwardly directed reflectingsurface positioned below said light source and spaced therefrom, theupper edge of said reflector terminating below said light source, saidsecondary reflector intercepting the greater portion but not all of saidrearwardly directed rays and redirecting said greater portion forwardlyof said luminaire in the direction of travel on the roadway, the spaceabove said reflector permitting the smaller portion of said rays to beemitted in a rearward direction. 7

2. A structure as set forth in claim 1, wherein said for- Wardlydirected reflecting surface of said secondary reflector is concavewhereby the intercepted rays are focused as well as redirected.

3. A structure as set forth in claim 1, wherein said elongated lightsource comprises at least three elongated tubes, the greater number ofsaid tubes being positioined on the forward side of said secondaryreflector and the smaller number said tubes being positioned on therearward side of said reflector.

References Cited in the file of this patent UNITED STATES PATENTS2,214,861 Oneil Sept. 17, 1940 2,304,202 Pracht Dec. 8, 1942 2,321,701Potter June 15, 1943 2,739,226 ReX Mar. 20, 1956 2,800,576 Epperson July23, 1957 FOREIGN PATENTS 876,085 Germany May 7, 1953

1. AN ELONGATED STREET LIGHTING LUMINAIR FOR USE ABOVE A ROADWAY HAVING UNIDIRECTIONAL TRAVEL THEREON DEFINING A FORWARD AND REARWARD DIRECTION, SAID LUMINAR HAVING AN ELONGATED HOUSING, BRACKET ARM ENGAGING SAID HOUSING AND SUPPORTING SAID LUMINAIR ABOVE THE ROADWAY WITH ITS LONGITUDINAL AXIS EXTENDING TRANSVERSAL OF SAID ROADWAY, AN ELONGATED LIGHT SOURCE SUPPORTED BY SAID HOUSING AND EXTENDING LONGITUDINALLY THEREOF, MEANS INCLUDING A GENERALLY HORIZONTALLY DISPOSED REFLECTING SURFACE POSITIONED ABOVE SAID LIGHT SOURCE FOR REFLECTING LIGHT RAYS FROM SAID SOURCE DOWNWARDLY IN A SUBSTANTIALLY BALANCED PATTERN, WITH SAID RAYS EXTENDING VERTICALLY AND ALSO AT AN ANGLE FORWARDLY AND REARWARDLY OF SAID LUMINAIR, AND MEANS INCLUDING A SECONDARY REFLECTOR HAVING A FORWARDLY DIRECTED REFLECTING SURFACE POSITIONED BELOW SAID LIGHT SOURCE AND SPACED THEREFROM, THE UPPER EDGE OF SAID REFLECTOR TERMINATING BELOW SAID LIGHT SOURCE, SAID SECONDARY REFLECTOR INTERCEPTING THE GREATER PORTION BUT NOT ALL OF SAID REARWARDLY DIRECTED RAY AND REDIRECTING SAID GREATER PORTION FORWARDLY OF SAID LUMINAIR IN THE DIRECTION OF TRAVEL ON THE ROADWAY, THE SPACE ABOVE SAID REFLECTOR PERMITTING THE SMALLER PORTION OF SAID RAYS TO BE EMITTED IN A REARWARD DIRECTION. 